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308 subsonic ammo


khanimran
04-03-2015, 12:52 PM
It is I....subsonic man. Kiwi here is a quick run down on subsonic .308 ammo.

Bullets....It is best to use a 1:10 or 1:8 twist barrel on your weapon. I have a 1:12 twist barrel on my 700 P and I get marginal performance. A good manufactured subsonic round at 100 yards or meters should yield a group of .50 to .75 MOA with the fast twist barrels. With my slow twist I get anywhere from 1" to 3" groups at 100 yards or meters.

I was taught to use jacketed flat top heavy bullets. The one I use the most is the Hornady 170 grain jacketed flat top bullet. Lapua and Swiss P market a subsonic round using pointed bullets, they may work good in fast twist rifles. I was taught to use long cylindirical bullets like the Hornady. Now, with the fast twist rifling you can use the heavier bullets, from 170 grains to I have seen some over 200 grains.

If you have a chronograph, you want to strive for a muzzle velocity of between 1000 fps to 1070 fps depending on the weight of the bullet. It has been suggested that the primer flash hole be enlarged and a magnum rifle primer used to ensure that the powder is ignited properly. DO NOT USE ANY FILLER IN THE CARTRIDGE WITH THE SMALL POWDER CHARGE.

DO NOT USE ANY TYPE OF RIFLE POWDER FOR YOUR PROPELLANT. IF YOU DO YOU CAN DEVELOP A SECONDARY EXPLOSION WHICH WILL RUIN YOUR DAY AND MAYBE YOUR LIFE. USE ONLY THE FASTEST PISTOL POWDERS SUCH AS RED DOT, BULLSEYE, OR UNIQUE.

As for cases, some people recommend reaming the primer flash hole to 9/64" or 3.5 mm. Mark these cases and use them for subsonic loads only. I had purchased some subsonic ammo from one outfit and they used the standard primer flash hole with out enlarging it. u can visit http://www.beckammunition.com/

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